US20040039290A1 - Cuff pulse wave detecting apparatus and pulse-wave-propagation-velocity-related information obtaining device - Google Patents
Cuff pulse wave detecting apparatus and pulse-wave-propagation-velocity-related information obtaining device Download PDFInfo
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- US20040039290A1 US20040039290A1 US10/395,300 US39530003A US2004039290A1 US 20040039290 A1 US20040039290 A1 US 20040039290A1 US 39530003 A US39530003 A US 39530003A US 2004039290 A1 US2004039290 A1 US 2004039290A1
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- cuff
- pulse
- wave
- propagation
- pulse wave
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/021—Measuring pressure in heart or blood vessels
- A61B5/02141—Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/021—Measuring pressure in heart or blood vessels
- A61B5/022—Measuring pressure in heart or blood vessels by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/026—Measuring blood flow
- A61B5/0285—Measuring or recording phase velocity of blood waves
Definitions
- the present invention relates to a cuff pulse wave detecting apparatus for detecting a cuff pulse wave as a pressure oscillation transmitted from a living subject to a cuff that is worn on the subject. Further, the present invention relates to a pulse-wave-propagation-velocity-related information obtaining apparatus for obtaining pulse-wave-propagation-velocity-related information which is related to a pulse-wave propagation velocity at which a pulse wave propagates to prescribed two body portions of a living subject, by using the cuff pulse wave detecting apparatus.
- a pulse wave detecting apparatus for detecting a pulse wave from a prescribed body portion of the subject.
- a pulse wave detecting apparatus there is used a cuff pulse wave detecting apparatus which includes a cuff adapted to be worn on the body portion such as an upper arm and detects a cuff pulse wave as a pressure oscillation that is transmitted from the subject to the cuff.
- the cuff pulse wave detecting apparatus is employed as the pulse wave detecting apparatus, many constituent elements or parts of the cuff pulse wave detecting apparatus can be utilized for measuring a blood pressure of the subject. Namely, the cuff pulse wave detecting apparatus also functions as a blood pressure measuring apparatus.
- the cuff pulse wave as the pressure oscillation produced in the cuff is transmitted to a pressure sensor via a pipe connecting between the cuff and the pressure sensor, and the cuff pulse wave transmitted to the pressure sensor is converted into an electric signal.
- the cuff pulse wave detecting apparatus it takes a certain time period for the cuff pulse wave produced in the cuff to propagate via the pipe to the pressure sensor. Accordingly, the electric signal representing the cuff pulse wave is obtained the certain time period after the cuff pulse wave has been produced.
- a cuff pulse wave detecting apparatus comprising: a main portion; a cuff which is remote from the main portion and which is adapted to be worn on a body portion of a living subject; and a pressure sensor which is connected to the cuff for detecting a pressure in the cuff, the cuff pulse wave detecting apparatus detecting a cuff pulse wave as a pressure oscillation transmitted from the subject to the cuff, wherein the pressure sensor is provided between the main portion and the cuff.
- a distance between the pressure sensor and the cuff is shorter than that in a conventional apparatus wherein a pressure sensor is accommodated in a main portion of the apparatus. Accordingly, the present arrangement is effective to reduce a time period required for the cuff pulse wave produced in the cuff to propagate to the pressure sensor. Therefore, the present cuff pulse wave detecting apparatus is capable of detecting, from the living subject, the cuff pulse wave that is substantially free from the problem of time or phase delay. While the pressure sensor is provided between the main portion and the cuff in the present apparatus, the pressure sensor may be provided in the cuff or may be supported by the cuff.
- a cuff pulse wave detecting apparatus comprising: a main portion; a cuff which is remote from the main portion and which is adapted to be worn on a body portion of a living subject; and a pressure sensor which is connected to the cuff via a pipe for detecting a pressure in the cuff, the cuff pulse wave detecting apparatus detecting a cuff pulse wave as a pressure oscillation transmitted from the subject to the cuff, wherein the pipe connecting between the pressure sensor and the cuff has a length that assures that a time needed for the cuff pulse wave produced in the cuff to propagate via the pipe to the pressure sensor is shorter than a shortest measurable time.
- the length of the pipe connecting between the pressure sensor and the cuff is made sufficiently short such that the time needed for the cuff pulse wave produced in the cuff to propagate via the pipe to the pressure sensor is shorter than the shortest measurable time.
- the shortest measurable time may correspond to the shortest operation time period of a signal processing device at which signals indicative of the pressure in the cuff and detected by the pressure sensor are read in.
- the shortest measurable time or the shortest operation time period will be described in greater detail in the DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS. Therefore, the cuff pulse wave detected by the present cuff pulse wave detecting apparatus is substantially free from the problem of time or phase delay.
- the cuff pulse wave detecting apparatus is used in a pulse-wave-propagation-velocity-related information obtaining apparatus for obtaining pulse-wave-propagation-velocity-related information that is related to a pulse-wave propagation velocity at which a pulse wave propagates to two body portions of a living subject, based on two heartbeat-synchronous signals respectively detected from the two body portions.
- the pulse-wave-propagation-velocity-related information obtaining apparatus comprises the cuff pulse wave detecting apparatus according to the above-described first or second aspect; and wherein one of the two heartbeat-synchronous signals comprise the cuff pulse wave detected by the cuff pulse wave detecting apparatus.
- the present pulse-wave-propagation-velocity-related information obtaining apparatus uses, as one of the two heartbeat-synchronous signals for obtaining the pulse-wave-propagation-related information, the cuff pulse wave which is detected by the above-described cuff pulse wave detecting apparatus and which is substantially free from the problem of time delay or phase delay. Therefore, accurate pulse-wave-propagation-velocity-related information can be obtained.
- the pulse-wave-propagation-velocity-related information obtaining apparatus uses, as the two heartbeat-synchronous signals, the respective two cuff pulse waves detected by the two cuff pulse wave detecting apparatuses each according to the above-described first or second aspect of the invention.
- the pulse-wave-propagation-velocity-related information obtaining apparatus comprises the two cuff pulse wave detecting apparatuses, each according to the above-described first or second aspect of the invention, whose respective cuffs are adapted to be worn on the two body portions, for detecting the respective cuff pulse waves from the two body portions; and wherein the two heartbeat-synchronous signals comprise the respective cuff pulse waves detected by the two cuff pulse wave detecting apparatuses.
- the present pulse-wave-propagation-velocity-related information obtaining apparatus uses, as the two heartbeat-synchronous signals, the respective cuff pulse waves detected by the two cuff pulse wave detecting apparatuses constructed as described above. Therefore, more accurate pulse-wave-propagation-related information can be obtained.
- FIG. 1 is a perspective view schematically showing a construction of a pulse-wave-propagation-velocity-related information obtaining apparatus to which the present invention is applied;
- FIG. 2 is a cross sectional view taken along line 2 - 2 of FIG. 1;
- FIG. 3 is a view showing a front surface of the main body of the apparatus of FIG. 1;
- FIG. 4 is a block diagram for explaining a control circuit of the apparatus of FIG. 1;
- FIG. 5 is a flow chart for explaining essential control functions of a CPU (central processing unit) of the apparatus of FIG. 1 that are needed for determining a pulse-wave propagation velocity PWV.
- FIG. 1 schematically shows a construction of a pulse-wave-propagation-velocity-related information obtaining apparatus 10 to which the present invention is applied.
- the present apparatus 10 obtains pulse-wave-propagation-related information that is related to a pulse-wave propagation velocity at which a pulse wave propagates in a living subject, and also has a function of measuring a blood pressure of the subject
- the pulse-wave-propagation-velocity-related-information obtaining apparatus 10 shown in FIG. 1 includes: a box-like main body 12 ; a left upper-arm cuff 14 L and a right upper-arm cuff 14 R adapted to be worn respectively on a left and a right upper arm of the subject; and a left ankle cuff 16 L and a right ankle cuff 16 R adapted to be worn respectively on a left and a right ankle of the subject.
- the left and right upper-arm cuffs 14 L, 14 R are connected to the main body 12 via a pipe 18 and a pipe 20 , respectively.
- the left and right ankle cuffs 16 L, 16 R are connected to the main body 12 via a pipe 24 and a pipe 26 , respectively. Respective portions of the two pipes 24 , 26 that are near to the main body 12 are covered with an outer sleeve 22 .
- a cuff-pulse-wave detecting unit 28 is provided at a position of the pipe 20 connecting between the right upper-arm cuff 14 R and the main body 12 , which position is remote from the right upper-arm cuff 14 R by a distance of not greater than 50 cm (e.g., 50 cm or 40 cm).
- the cuff-pulse-wave detecting unit 28 includes a first pressure sensor 30 having a pressure detecting portion 30 a , and a pulse-wave filter circuit 32 .
- the first pressure sensor 30 and the pulse-wave filter circuit 32 are accommodated in a protective case 34 .
- the first pressure sensor 30 is attached to the outer circumferential surface of the pipe 20 such that the pressure detecting portion 30 a projects into an inner space of the pipe 20 through its wall, so that the pressure detecting portion 30 a is exposed to the inner space of the pipe 20 for detecting a first air pressure P 1 in the pipe 20 .
- the first pressure sensor 30 outputs a first pressure signal SP 1 representing the detected first air pressure P 1 in the pipe 20 .
- the pulse-wave filter circuit 32 includes a band-pass filter and extracts, from the first pressure signal SP 1 , a first cuff-pulse-wave signal SM 1 as an oscillatory component of the first air pressure P 1 detected by the first pressure sensor 30 .
- the first pressure sensor 30 there may be employed an electronic pressure sensor of semiconductor piezoresistance type, semiconductor capacitance type, or thin-film type.
- the oscillatory component extracted from the first pressure signal SP 1 by the pulse-wave filter circuit 32 represents a cuff pulse wave produced in the right upper-arm cuff 14 R, i.e., a pulse wave produced from a brachial artery of the right upper arm of the subject and is propagated to the right upper-arm cuff 14 R.
- the pulse-wave filter circuit 32 supplies the first cuff-pulse-wave signal SM 1 indicative of the cuff pulse wave to the main body 12 via an electric wire (signal wire) 36 .
- the first pressure signal SP 1 outputted from the first pressure sensor 30 is the same as the first cuff-pulse-wave signal SM 1 except that the first pressure signal SP 1 contains a static-pressure component in addition to the oscillatory component, the first air pressure P 1 represented by the first pressure signal SP 1 may be considered as a cuff pulse wave. Since a cuff pulse wave is produced in synchronism with the heartbeat of the subject, the cuff pulse wave is a heartbeat-synchronous signal.
- a cuff-pulse-wave detecting unit 38 is provided at respective positions of the pipes 24 , 26 , which positions are nearer to the left and right ankle cuffs 16 L, 16 R than the portions thereof covered with the outer sleeve 22 . Described in detail, the cuff-pulse-wave detecting unit 38 is attached to the pipes 24 , 26 so as to cover the pipes 24 , 26 , such that the detecting unit 38 is remote from the left and right ankle cuffs 16 L, 16 R by a distance of not greater than 50 cm.
- the cuff-pulse-wave detecting unit 38 includes two first pressure sensors 39 similar in construction to the first pressure sensor 30 of the cuff-pulse-wave detecting unit 28 , and two pulse-wave filter circuits 40 similar in construction to the pulse-wave filter circuit 32 of the detecting unit 28 .
- the two first pressure sensors 39 respectively detect a second air pressure P 2 in the pipe 24 for the left ankle cuff 16 L and a third air pressure P 3 in the pipe 26 for the right ankle cuff 16 R.
- the two pulse-wave filter circuits 40 respectively extract a second cuff-pulse-wave signal SM 2 as an oscillatory component of the detected second air pressure P 2 , and a third cuff-pulse-wave signal SM 3 as an oscillatory component of the detected third air pressure P 3 .
- the second and third cuff-pulse-wave signals SM 2 , SM 3 represent respective cuff pulse waves.
- the second and third cuff-pulse-wave signals SM 2 , SM 3 extracted by the respective two pulse-wave-filter circuits 40 of the cuff-pulse-wave detecting unit 38 are supplied to the main body 12 via an electric wire (signal wire) 41 .
- FIG. 3 shows a front surface 42 of the main body 12 .
- a plurality of input keys through which a name, an identification number, a stature, and other information of a patient are inputted, and a display device 46 which displays a measured pulse-wave propagation velocity PWV of the patient.
- FIG. 4 is a block diagram for explaining a circuit of the present pulse-wave-propagation-velocity-related information obtaining apparatus 10 .
- the circuit for the left ankle cuff 16 L is the same as that of the right ankle cuff 16 R.
- the circuit for changing a pressing pressure of the left upper-arm cuff 14 L and detecting the cuff pulse wave produced in the left upper-arm cuff 14 L is the same as that for the right upper-arm cuff 14 R, except that the circuit for the left upper-arm cuff 14 L includes, in place of the cuff-pulse-wave detecting unit 28 , a pressure sensor corresponding to a second pressure sensor 56 of a cuff-pressure changing portion 48 (which will be described), and a static-pressure filter circuit 62 (which will be described) and a pulse-wave filter circuit 32 that are connected to the pressure sensor.
- the circuits for the left ankle cuff 16 L and the left upper-arm cuff 14 L are omitted from the block diagram of FIG. 4.
- the cuff-pressure changing portion 48 accommodated in the main body 12 detects a pressing pressure of the right upper-arm cuff 14 R (hereinafter referred to as “the first cuff pressure PC 1 ), and changes or controls the first cuff pressure PC 1 .
- the cuff-pressure changing portion 48 includes: a pipe 52 connected to the pipe 20 for the right upper-arm cuff 14 R; a pressure control valve 54 and the second pressure sensor 56 which are connected to the pipe 52 ; an air pump 60 connected to the pressure control valve 54 via a pipe 58 ; the static-pressure filter circuit 62 ; and an A/D (analog to digital) converter 64 .
- the pressure control valve 54 adjusts a pressure of a pressurized air supplied from the air pump 60 , and supplies the pressure-adjusted air to the right upper-arm cuff 14 R, or discharges the pressurized air from the right upper-arm cuff 14 R, so as to control an air pressure in the right upper-arm cuff 14 R.
- the second pressure sensor 56 detects a first air pressure P 1 in the pipe 20 for the right upper-arm cuff 14 R, and supplies a first pressure signal SP 1 representing the detected first air pressure P 1 to the static-pressure filter circuit 62 .
- the static-pressure filer circuit 62 has a low-pass filter and extracts, from the first pressure signal SP 1 , a first cuff-pressure signal SC 1 representing a static-pressure component contained in the first pressure signal SP 1 .
- the first cuff-pressure signal SC 1 is supplied to an electronic control device 66 via an A/D converter 64 .
- the first cuff-pulse-wave signal SM 1 extracted from the first pressure signal SP 1 by the pulse-wave filter circuit 32 is supplied to the control device 66 via an A/D converter 68 . Further, the signals respectively representing the name, identification number, and stature of the patient, which signals have been inputted through the input keys 44 , are supplied to the control device 66 .
- a cuff-pressure changing portion 70 is similar in construction to the cuff-pressure changing portion 48 described above.
- a pipe 52 is connected to the pipe 26 for the right ankle cuff 16 R, and a static-pressure filter circuit 62 extracts a third cuff-pressure-signal SC 3 representing a pressing pressure of the right ankle cuff 16 R, i.e., a third cuff pressure PC 3 .
- the third cuff-pressure signal SC 3 is supplied to the control device 66 .
- the third cuff-pulse-wave signal SM 3 extracted by the pulse-wave filter circuit 40 of the cuff-pulse-wave detecting unit 38 is also supplied to the control device 66 via an A/D converter 72 .
- the electronic control device 66 is essentially provided by a so-called microcomputer including a CPU (central processing unit) 74 , a ROM (read only memory) 76 , a RAM (random access memory) 78 , an input-and-output (I/O) port, not shown, etc., and the CPU 74 processes signals according to control programs pre-stored in the ROM 76 , while utilizing a temporary-storage function of the RAM 78 .
- a CPU central processing unit
- ROM read only memory
- RAM random access memory
- I/O input-and-output
- the control device 66 determines the first and third cuff pressures PC 1 , PC 3 based on the first and third cuff-pressure signals SC 1 , SC 3 respectively supplied from the static-pressure filter circuits 62 , and outputs, from the I/O port, drive signals to the air pumps 60 and the pressure control valves 54 so as to control the respective operations thereof and thereby control the first and third cuff pressures PC 1 , PC 3 to respective pre-set pulse-wave detecting pressures for measuring a pulse-wave propagation velocity PWV.
- the pulse-wave detecting pressures are expected to be lower than diastolic blood pressure values of the body portions of the subject around which the right upper-arm cuff 14 R and the right ankle cuff 16 R are respectively wound, but permit the pulse-wave signals SM 1 , SM 3 extracted by the pulse-wave filter circuits 32 , 40 to have a sufficiently great magnitude.
- the pulse-wave detecting pressures are pre-set at 50 mmHg, for instance.
- control device 66 controls the air pumps 60 and the pressure control valves 54 of the cuff-pressure changing portions 48 , 70 , so as to control the first and third cuff pressures PC 1 , PC 3 to the respective pulse-wave detecting pressures, and the cuff-pulse-wave signals SM 1 , SM 3 representing the respective cuff pulse waves are respectively detected by the pulse-wave filter circuit 32 of the cuff-pulse-wave detecting unit 28 and the pulse-wave filter circuit 40 of the cuff-pulse-wave detecting unit 38 .
- the right upper-arm cuff 14 R, cuff-pulse-wave detecting unit 28 , cuff-pressure changing portion 48 , and control device 66 cooperate with one another to provide a right-upper-arm-cuff-pulse-wave detecting apparatus 80 .
- the right ankle cuff 16 R, cuff-pulse-wave detecting unit 38 , cuff-pressure changing portion 70 , and control device 66 cooperate with one another to provide a right-ankle-cuff-pulse-wave detecting apparatus 82 .
- the CPU 74 further determines the pulse-wave propagation velocity PWV based on the cuff-pulse-wave signals SM 1 , SM 3 respectively supplied from the pulse-wave filter circuits 32 , 40 when the cuff pressures PC 1 , PC 3 are kept at the respective pulse-wave detecting pressures.
- the determined pulse-wave propagation velocity PWV is displayed by the display device 46 .
- the cuff-pulse-wave signals SM 1 , SM 3 supplied to the control device 66 are read in at the shortest operation time period that corresponds to a clock frequency f of the CPU 74 .
- This shortest operation time period means the shortest measurable time.
- the clock frequency f is not particularly limited, and is suitably determined depending upon a speed at which the CPU 74 is required to process signals, a cost at which the CPU 74 is required to be manufactured, etc.
- the clock frequency f of the CPU 74 is 600 Hz
- the shortest operation time period, i.e., the shortest measurable time is 1.67 msec (millisecond).
- the velocity at which the cuff pulse waves as the pressure oscillations produced in the right upper-arm cuff 14 R and the left and right ankle cuffs 16 L, 16 R propagate in the pipes 20 , 24 , 26 varies depending upon the kind of the medium (i.e., the air) that transmits the pressure, the diameter and material of the pipes, etc.
- the pulse waves propagate a distance of 1 m in from 2 ms to 3 ms.
- the time needed for the cuff pulse waves produced in the right upper-arm cuff 14 R and the left and right ankle cuffs 16 L, 16 R to propagate via the pipes 20 , 24 , 26 and be detected by the first pressure sensors 30 , 39 of the cuff-pulse-wave detecting units 28 , 38 does not cause the problem of time delay.
- the CPU 74 controls the air pumps 60 and the pressure control valves 54 of the cuff-pressure changing portions 40 , 70 , and air pumps 60 and pressure control valves 54 (both of which are not shown) for controlling the pressing pressures of the left upper-arm cuff 14 L and the left ankle cuff 16 L, and thereby controls the pressing pressures of the four cuffs 14 L, 14 R, 16 L, 16 R as follows: First, the pressing pressures of the four cuffs 14 L, 14 R, 16 L, 16 R are quickly increased to a pre-set target pressure. Then, the pressing pressures of the four cuffs 14 L, 14 R, 16 L, 16 R are slowly decreased at a prescribed rate.
- the CPU 74 determines, according to a well-known oscillometric algorithm, blood pressure values of the superior limbs and the inferior limbs of the subject, based on the signals continuously supplied from the four static-pressure, filter circuits and the four pulse-wave filter circuits.
- FIG. 5 is a flow chart for explaining essential control functions of the CPU 74 that are needed for determining a pulse-wave propagation velocity PWV
- the present pulse-wave-propagation-velocity-related information obtaining apparatus 10 is arranged to determine a pulse-wave propagation velocity at which a pulse wave propagates to the right upper arm and the right ankle, and a pulse-wave propagation velocity at which a pulse wave propagates to the right upper arm and the left ankle. Since the respective control functions of the CPU 74 for determining the two pulse-wave propagation velocity values PWV are identical with each other, the control routine of FIG. 5 shows the control functions for determining the pulse-wave propagation velocity at which the pulse wave propagates to the right upper arm and the right ankle.
- Step S 1 (hereinafter, “Step” is omitted, if appropriate) to drive the air pumps 60 of the cuff-pressure changing portions 48 , 70 , and operate the pressure control valves 54 of the cuff-pressure changing portions 48 , 70 , so as to change the first cuff-pressure PC 1 and the third cuff-pressure PC 3 to the respective pre-set pulse-wave detecting pressures.
- S 1 is followed by S 2 in which the CPU 74 reads in respective one-heartbeat lengths of the cuff-pulse-wave signals SM 1 , SM 3 respectively supplied from the pulse-wave filter circuits 32 , 40 .
- S 3 is implemented to stop the air pumps 60 and operate the pressure control valves 54 of the cuff-pressure changing portions 48 , 70 , so as to release the first and third cuff-pressures PC 1 , PC 3 to an atmospheric pressure.
- the CPU carries out S 4 to determine a time of detection of a reference point of the cuff pulse wave represented by the signal SM 1 and a time of detection of a corresponding reference point of the cuff pulse wave represented by the signal SM 3 , which signals SM 1 , SM 3 have been read in at S 2 .
- a reference point a rising point or a peak point of each cuff pulse wave is employed.
- S 4 is followed by S 5 in which the CPU 74 obtains, as a pulse-wave propagation time DT, a time difference between the times of detection of the two reference points of the two cuff pulse waves.
- S 5 is followed by S 6 to obtain, according to the following Expression (1), a propagation distance L1 as a difference between respective distances of the right upper arm and the right ankle from the heart of the subject, based on the stature T inputted through the input keys 44 .
- S 6 is followed by S 7 in which the CPU 74 substitutes the pulse-wave propagation time DT obtained at S 5 and the pulse-wave propagation distance L1 obtained at S 6 , with the following Expression (2), thereby determining a pulse-wave propagation velocity PWV.
- the CPU 74 operates the display device 46 to display the determined pulse-wave propagation velocity PWV.
- the cuff-pulse-wave detecting units 28 , 38 having the respective first pressure sensors 30 , 39 are respectively provided between the main body 12 and the right upper-arm cuff 14 R, and between the main body 12 and the left and right ankle cuffs 16 L, 16 R, the distances between the right upper-arm cuff 14 R and the first pressure sensor 30 and between the left and right ankle cuffs 16 L, 16 R and the first pressure sensor 39 are shorter than those of a conventional arrangement wherein first pressure sensors 30 , 39 are accommodated in a main body 12 .
- the present arrangement effectively reduces a time required for the cuff pulse waves produced in the cuffs 14 R, 16 L, 16 R to propagate to the first pressure sensors 30 , 39 , so that the obtained cuff pulse waves are substantially free from the problem of time or phase delay.
- the length of the pipe 18 connecting between the cuff 14 R and the first pressure sensor 30 , the length of the pipe 24 connecting between the cuff 16 L and the first pressure sensor 39 , and the length of the pipe 26 connecting between the cuff 16 R and the first pressure sensor 39 are made sufficiently short such that the time needed for the cuff pulse waves produced in the cuffs 14 R, 16 L, 16 R to propagate via the pipes 18 , 24 , 26 to the pressure sensors 30 , 39 are shorter than the shortest operation time period of the CPU 74 at which the cuff-pulse-wave signals SM 1 , SM 3 are read in. Accordingly, the cuff pulse waves obtained by the present apparatus are substantially free from the problem of time or phase delay.
- the cuff pulse waves substantially free from the problem of time delay are used as the two heartbeat-synchronous signals used for determining the pulse-wave propagation velocity PWV, so that the pulse-wave propagation velocity PWV can be accurately determined.
- the first pressure sensor 30 is provided between the cuff 14 R and the main body 12 and the first pressure sensors 39 are provided between the cuffs 16 L, 16 R and the main body 12 .
- the first pressure sensor 30 may be provided in the cuff 14 R or supported by the cuff 14 R, and the first pressure sensors 39 may be respectively provided in the cuffs 16 L, 16 R, or respectively supported by the cuffs 16 L, 16 R.
- the two cuff pulse waves are used as the two heartbeat-synchronous signals for determining the pulse-wave propagation velocity PWV.
- the two heartbeat-synchronous signals there may be used any one of a heart sound, an electrocardiographic waveform (electrocardiogram), and a photoelectric pulse wave detected by a photoelectric-pulse-wave detecting sensor adapted to be worn on, e.g., an end portion of a finger of a living subject.
- the pulse-wave filter circuits 32 , 40 are accommodated in the cuff-pulse-wave detecting units 28 , 38 , respectively.
- the pulse-wave filter circuits 32 , 40 may be accommodated in the main body 12 .
- the cuff pulse waves extracted by the pulse-wave filter circuits 32 , 40 may be utilized to obtain physical information of the subject other than the pulse-wave-propagation-velocity-related information, such as an augmentation index, or an ejection time or period that starts with starting of ejection of blood from the left ventricle by opening of the aortic valve and ends with closing of the aortic valve.
Abstract
Description
- 1. Field of the Invention
- The present invention relates to a cuff pulse wave detecting apparatus for detecting a cuff pulse wave as a pressure oscillation transmitted from a living subject to a cuff that is worn on the subject. Further, the present invention relates to a pulse-wave-propagation-velocity-related information obtaining apparatus for obtaining pulse-wave-propagation-velocity-related information which is related to a pulse-wave propagation velocity at which a pulse wave propagates to prescribed two body portions of a living subject, by using the cuff pulse wave detecting apparatus.
- 2. Related Art Statement
- For obtaining physical information of a living subject such as pulse-wave-propagation-velocity-related information, a pulse wave detecting apparatus for detecting a pulse wave from a prescribed body portion of the subject is used. As the pulse wave detecting apparatus, there is used a cuff pulse wave detecting apparatus which includes a cuff adapted to be worn on the body portion such as an upper arm and detects a cuff pulse wave as a pressure oscillation that is transmitted from the subject to the cuff. Where the cuff pulse wave detecting apparatus is employed as the pulse wave detecting apparatus, many constituent elements or parts of the cuff pulse wave detecting apparatus can be utilized for measuring a blood pressure of the subject. Namely, the cuff pulse wave detecting apparatus also functions as a blood pressure measuring apparatus.
- In the cuff pulse wave detecting apparatus, the cuff pulse wave as the pressure oscillation produced in the cuff is transmitted to a pressure sensor via a pipe connecting between the cuff and the pressure sensor, and the cuff pulse wave transmitted to the pressure sensor is converted into an electric signal. In the cuff pulse wave detecting apparatus, it takes a certain time period for the cuff pulse wave produced in the cuff to propagate via the pipe to the pressure sensor. Accordingly, the electric signal representing the cuff pulse wave is obtained the certain time period after the cuff pulse wave has been produced. In other words, there is a time lag or delay between the cuff pulse wave detected by the above-described cuff pulse wave detecting apparatus and an actual pulse wave of the subject, the time delay corresponding to the time period needed for the cuff pulse wave to propagate to the pressure sensor after it has been produced in the cuff. Further, the cuff pulse wave detected by the cuff pulse wave detecting apparatus may suffer from a phase lag or delay. Thus, the accuracy of the physical information obtained through the conventional cuff pulse wave detecting apparatus is insufficient.
- It is therefore an object of the present invention to provide a cuff pulse wave detecting apparatus capable of detecting, from a living subject, a cuff pulse wave which is substantially free from the problem of time or phase delay.
- The above-indicated object has been achieved by a first aspect of the present invention according to which there is provided a cuff pulse wave detecting apparatus comprising: a main portion; a cuff which is remote from the main portion and which is adapted to be worn on a body portion of a living subject; and a pressure sensor which is connected to the cuff for detecting a pressure in the cuff, the cuff pulse wave detecting apparatus detecting a cuff pulse wave as a pressure oscillation transmitted from the subject to the cuff, wherein the pressure sensor is provided between the main portion and the cuff.
- In the cuff pulse wave detecting apparatus according to this aspect, a distance between the pressure sensor and the cuff is shorter than that in a conventional apparatus wherein a pressure sensor is accommodated in a main portion of the apparatus. Accordingly, the present arrangement is effective to reduce a time period required for the cuff pulse wave produced in the cuff to propagate to the pressure sensor. Therefore, the present cuff pulse wave detecting apparatus is capable of detecting, from the living subject, the cuff pulse wave that is substantially free from the problem of time or phase delay. While the pressure sensor is provided between the main portion and the cuff in the present apparatus, the pressure sensor may be provided in the cuff or may be supported by the cuff.
- According to a second aspect of the present invention, there is provided a cuff pulse wave detecting apparatus comprising: a main portion; a cuff which is remote from the main portion and which is adapted to be worn on a body portion of a living subject; and a pressure sensor which is connected to the cuff via a pipe for detecting a pressure in the cuff, the cuff pulse wave detecting apparatus detecting a cuff pulse wave as a pressure oscillation transmitted from the subject to the cuff, wherein the pipe connecting between the pressure sensor and the cuff has a length that assures that a time needed for the cuff pulse wave produced in the cuff to propagate via the pipe to the pressure sensor is shorter than a shortest measurable time.
- In the cuff pulse wave detecting apparatus according to the second aspect, the length of the pipe connecting between the pressure sensor and the cuff is made sufficiently short such that the time needed for the cuff pulse wave produced in the cuff to propagate via the pipe to the pressure sensor is shorter than the shortest measurable time. The shortest measurable time may correspond to the shortest operation time period of a signal processing device at which signals indicative of the pressure in the cuff and detected by the pressure sensor are read in. The shortest measurable time or the shortest operation time period will be described in greater detail in the DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS. Therefore, the cuff pulse wave detected by the present cuff pulse wave detecting apparatus is substantially free from the problem of time or phase delay.
- Preferably, the cuff pulse wave detecting apparatus, according to the above-indicated first or second aspect of the invention, is used in a pulse-wave-propagation-velocity-related information obtaining apparatus for obtaining pulse-wave-propagation-velocity-related information that is related to a pulse-wave propagation velocity at which a pulse wave propagates to two body portions of a living subject, based on two heartbeat-synchronous signals respectively detected from the two body portions. The pulse-wave-propagation-velocity-related information obtaining apparatus comprises the cuff pulse wave detecting apparatus according to the above-described first or second aspect; and wherein one of the two heartbeat-synchronous signals comprise the cuff pulse wave detected by the cuff pulse wave detecting apparatus. The present pulse-wave-propagation-velocity-related information obtaining apparatus uses, as one of the two heartbeat-synchronous signals for obtaining the pulse-wave-propagation-related information, the cuff pulse wave which is detected by the above-described cuff pulse wave detecting apparatus and which is substantially free from the problem of time delay or phase delay. Therefore, accurate pulse-wave-propagation-velocity-related information can be obtained.
- Preferably, the pulse-wave-propagation-velocity-related information obtaining apparatus uses, as the two heartbeat-synchronous signals, the respective two cuff pulse waves detected by the two cuff pulse wave detecting apparatuses each according to the above-described first or second aspect of the invention. The pulse-wave-propagation-velocity-related information obtaining apparatus comprises the two cuff pulse wave detecting apparatuses, each according to the above-described first or second aspect of the invention, whose respective cuffs are adapted to be worn on the two body portions, for detecting the respective cuff pulse waves from the two body portions; and wherein the two heartbeat-synchronous signals comprise the respective cuff pulse waves detected by the two cuff pulse wave detecting apparatuses. The present pulse-wave-propagation-velocity-related information obtaining apparatus uses, as the two heartbeat-synchronous signals, the respective cuff pulse waves detected by the two cuff pulse wave detecting apparatuses constructed as described above. Therefore, more accurate pulse-wave-propagation-related information can be obtained.
- The above and optional objects, features, and advantages of the present invention will be better understood by reading the following detailed description of the preferred embodiments of the invention when considered in conjunction with the drawings, in which:
- FIG. 1 is a perspective view schematically showing a construction of a pulse-wave-propagation-velocity-related information obtaining apparatus to which the present invention is applied;
- FIG. 2 is a cross sectional view taken along line2-2 of FIG. 1;
- FIG. 3 is a view showing a front surface of the main body of the apparatus of FIG. 1;
- FIG. 4 is a block diagram for explaining a control circuit of the apparatus of FIG. 1; and
- FIG. 5 is a flow chart for explaining essential control functions of a CPU (central processing unit) of the apparatus of FIG. 1 that are needed for determining a pulse-wave propagation velocity PWV.
- Hereinafter, there will be described an embodiment of the present invention in detail by reference to the drawings. FIG. 1 schematically shows a construction of a pulse-wave-propagation-velocity-related
information obtaining apparatus 10 to which the present invention is applied. Thepresent apparatus 10 obtains pulse-wave-propagation-related information that is related to a pulse-wave propagation velocity at which a pulse wave propagates in a living subject, and also has a function of measuring a blood pressure of the subject - The pulse-wave-propagation-velocity-related-
information obtaining apparatus 10 shown in FIG. 1 includes: a box-likemain body 12; a left upper-arm cuff 14L and a right upper-arm cuff 14R adapted to be worn respectively on a left and a right upper arm of the subject; and aleft ankle cuff 16L and aright ankle cuff 16R adapted to be worn respectively on a left and a right ankle of the subject. The left and right upper-arm cuffs main body 12 via apipe 18 and apipe 20, respectively. The left andright ankle cuffs main body 12 via apipe 24 and apipe 26, respectively. Respective portions of the twopipes main body 12 are covered with anouter sleeve 22. - A cuff-pulse-
wave detecting unit 28 is provided at a position of thepipe 20 connecting between the right upper-arm cuff 14R and themain body 12, which position is remote from the right upper-arm cuff 14R by a distance of not greater than 50 cm (e.g., 50 cm or 40 cm). - As shown in FIG. 2, the cuff-pulse-
wave detecting unit 28 includes afirst pressure sensor 30 having apressure detecting portion 30 a, and a pulse-wave filter circuit 32. Thefirst pressure sensor 30 and the pulse-wave filter circuit 32 are accommodated in aprotective case 34. Thefirst pressure sensor 30 is attached to the outer circumferential surface of thepipe 20 such that thepressure detecting portion 30 a projects into an inner space of thepipe 20 through its wall, so that thepressure detecting portion 30 a is exposed to the inner space of thepipe 20 for detecting a first air pressure P1 in thepipe 20. Thefirst pressure sensor 30 outputs a first pressure signal SP1 representing the detected first air pressure P1 in thepipe 20. The pulse-wave filter circuit 32 includes a band-pass filter and extracts, from the first pressure signal SP1, a first cuff-pulse-wave signal SM1 as an oscillatory component of the first air pressure P1 detected by thefirst pressure sensor 30. - As the
first pressure sensor 30, there may be employed an electronic pressure sensor of semiconductor piezoresistance type, semiconductor capacitance type, or thin-film type. - The oscillatory component extracted from the first pressure signal SP1 by the pulse-
wave filter circuit 32 represents a cuff pulse wave produced in the right upper-arm cuff 14R, i.e., a pulse wave produced from a brachial artery of the right upper arm of the subject and is propagated to the right upper-arm cuff 14R. The pulse-wave filter circuit 32 supplies the first cuff-pulse-wave signal SM1 indicative of the cuff pulse wave to themain body 12 via an electric wire (signal wire) 36. Since the first pressure signal SP1 outputted from thefirst pressure sensor 30 is the same as the first cuff-pulse-wave signal SM1 except that the first pressure signal SP1 contains a static-pressure component in addition to the oscillatory component, the first air pressure P1 represented by the first pressure signal SP1 may be considered as a cuff pulse wave. Since a cuff pulse wave is produced in synchronism with the heartbeat of the subject, the cuff pulse wave is a heartbeat-synchronous signal. - A cuff-pulse-
wave detecting unit 38 is provided at respective positions of thepipes right ankle cuffs outer sleeve 22. Described in detail, the cuff-pulse-wave detecting unit 38 is attached to thepipes pipes unit 38 is remote from the left andright ankle cuffs wave detecting unit 38 includes twofirst pressure sensors 39 similar in construction to thefirst pressure sensor 30 of the cuff-pulse-wave detecting unit 28, and two pulse-wave filter circuits 40 similar in construction to the pulse-wave filter circuit 32 of the detectingunit 28. The twofirst pressure sensors 39 respectively detect a second air pressure P2 in thepipe 24 for theleft ankle cuff 16L and a third air pressure P3 in thepipe 26 for theright ankle cuff 16R. The two pulse-wave filter circuits 40 respectively extract a second cuff-pulse-wave signal SM2 as an oscillatory component of the detected second air pressure P2, and a third cuff-pulse-wave signal SM3 as an oscillatory component of the detected third air pressure P3. The second and third cuff-pulse-wave signals SM2, SM3 represent respective cuff pulse waves. - The second and third cuff-pulse-wave signals SM2, SM3 extracted by the respective two pulse-wave-
filter circuits 40 of the cuff-pulse-wave detecting unit 38 are supplied to themain body 12 via an electric wire (signal wire) 41. - FIG. 3 shows a
front surface 42 of themain body 12. On thefront surface 42 of themain body 12, there are provided a plurality of input keys through which a name, an identification number, a stature, and other information of a patient are inputted, and adisplay device 46 which displays a measured pulse-wave propagation velocity PWV of the patient. - FIG. 4 is a block diagram for explaining a circuit of the present pulse-wave-propagation-velocity-related
information obtaining apparatus 10. The circuit for theleft ankle cuff 16L is the same as that of theright ankle cuff 16R. The circuit for changing a pressing pressure of the left upper-arm cuff 14L and detecting the cuff pulse wave produced in the left upper-arm cuff 14L is the same as that for the right upper-arm cuff 14R, except that the circuit for the left upper-arm cuff 14L includes, in place of the cuff-pulse-wave detecting unit 28, a pressure sensor corresponding to asecond pressure sensor 56 of a cuff-pressure changing portion 48 (which will be described), and a static-pressure filter circuit 62 (which will be described) and a pulse-wave filter circuit 32 that are connected to the pressure sensor. In view of the above, the circuits for theleft ankle cuff 16L and the left upper-arm cuff 14L are omitted from the block diagram of FIG. 4. - The cuff-
pressure changing portion 48 accommodated in themain body 12 detects a pressing pressure of the right upper-arm cuff 14R (hereinafter referred to as “the first cuff pressure PC1), and changes or controls the first cuff pressure PC1. The cuff-pressure changing portion 48 includes: apipe 52 connected to thepipe 20 for the right upper-arm cuff 14R; apressure control valve 54 and thesecond pressure sensor 56 which are connected to thepipe 52; anair pump 60 connected to thepressure control valve 54 via apipe 58; the static-pressure filter circuit 62; and an A/D (analog to digital)converter 64. - The
pressure control valve 54 adjusts a pressure of a pressurized air supplied from theair pump 60, and supplies the pressure-adjusted air to the right upper-arm cuff 14R, or discharges the pressurized air from the right upper-arm cuff 14R, so as to control an air pressure in the right upper-arm cuff 14R. - Like the
first pressure sensor 30 of the cuff-pulse-wave detecting unit 28, thesecond pressure sensor 56 detects a first air pressure P1 in thepipe 20 for the right upper-arm cuff 14R, and supplies a first pressure signal SP1 representing the detected first air pressure P1 to the static-pressure filter circuit 62. - The static-
pressure filer circuit 62 has a low-pass filter and extracts, from the first pressure signal SP1, a first cuff-pressure signal SC1 representing a static-pressure component contained in the first pressure signal SP1. The first cuff-pressure signal SC1 is supplied to anelectronic control device 66 via an A/D converter 64. - The first cuff-pulse-wave signal SM1 extracted from the first pressure signal SP1 by the pulse-
wave filter circuit 32 is supplied to thecontrol device 66 via an A/D converter 68. Further, the signals respectively representing the name, identification number, and stature of the patient, which signals have been inputted through theinput keys 44, are supplied to thecontrol device 66. - A cuff-
pressure changing portion 70 is similar in construction to the cuff-pressure changing portion 48 described above. In the cuff-pressure changing portion 70, apipe 52 is connected to thepipe 26 for theright ankle cuff 16R, and a static-pressure filter circuit 62 extracts a third cuff-pressure-signal SC3 representing a pressing pressure of theright ankle cuff 16R, i.e., a third cuff pressure PC3. The third cuff-pressure signal SC3 is supplied to thecontrol device 66. The third cuff-pulse-wave signal SM3 extracted by the pulse-wave filter circuit 40 of the cuff-pulse-wave detecting unit 38 is also supplied to thecontrol device 66 via an A/D converter 72. - The
electronic control device 66 is essentially provided by a so-called microcomputer including a CPU (central processing unit) 74, a ROM (read only memory) 76, a RAM (random access memory) 78, an input-and-output (I/O) port, not shown, etc., and theCPU 74 processes signals according to control programs pre-stored in theROM 76, while utilizing a temporary-storage function of theRAM 78. Described in detail, thecontrol device 66 determines the first and third cuff pressures PC1, PC3 based on the first and third cuff-pressure signals SC1, SC3 respectively supplied from the static-pressure filter circuits 62, and outputs, from the I/O port, drive signals to theair pumps 60 and thepressure control valves 54 so as to control the respective operations thereof and thereby control the first and third cuff pressures PC1, PC3 to respective pre-set pulse-wave detecting pressures for measuring a pulse-wave propagation velocity PWV. The pulse-wave detecting pressures are expected to be lower than diastolic blood pressure values of the body portions of the subject around which the right upper-arm cuff 14R and theright ankle cuff 16R are respectively wound, but permit the pulse-wave signals SM1, SM3 extracted by the pulse-wave filter circuits - As described above, the
control device 66 controls theair pumps 60 and thepressure control valves 54 of the cuff-pressure changing portions wave filter circuit 32 of the cuff-pulse-wave detecting unit 28 and the pulse-wave filter circuit 40 of the cuff-pulse-wave detecting unit 38. Accordingly, the right upper-arm cuff 14R, cuff-pulse-wave detecting unit 28, cuff-pressure changing portion 48, andcontrol device 66 cooperate with one another to provide a right-upper-arm-cuff-pulse-wave detecting apparatus 80. Theright ankle cuff 16R, cuff-pulse-wave detecting unit 38, cuff-pressure changing portion 70, andcontrol device 66 cooperate with one another to provide a right-ankle-cuff-pulse-wave detecting apparatus 82. - The
CPU 74 further determines the pulse-wave propagation velocity PWV based on the cuff-pulse-wave signals SM1, SM3 respectively supplied from the pulse-wave filter circuits display device 46. - The cuff-pulse-wave signals SM1, SM3 supplied to the
control device 66 are read in at the shortest operation time period that corresponds to a clock frequency f of theCPU 74. This shortest operation time period means the shortest measurable time. The clock frequency f is not particularly limited, and is suitably determined depending upon a speed at which theCPU 74 is required to process signals, a cost at which theCPU 74 is required to be manufactured, etc. In the present embodiment, the clock frequency f of theCPU 74 is 600 Hz, and the shortest operation time period, i.e., the shortest measurable time is 1.67 msec (millisecond). - The velocity at which the cuff pulse waves as the pressure oscillations produced in the right upper-
arm cuff 14R and the left and right ankle cuffs 16L, 16R propagate in thepipes information obtaining apparatus 10, the pulse waves propagate a distance of 1 m in from 2 ms to 3 ms. Accordingly, it takes from 1 ms to 1.5 ms or the shorter time for the cuff pulse waves to propagate from the right upper-arm cuff 14R and the left and right ankle cuffs 16L, 16R to the cuff-pulse-wave detecting units cuffs CPU 74 at which the cuff-pulse-wave signals SM1, SM3 are read in. Therefore, in the present arrangement, the time needed for the cuff pulse waves produced in the right upper-arm cuff 14R and the left and right ankle cuffs 16L, 16R to propagate via thepipes first pressure sensors wave detecting units - During a blood pressure measurement, the
CPU 74 controls theair pumps 60 and thepressure control valves 54 of the cuff-pressure changing portions air pumps 60 and pressure control valves 54 (both of which are not shown) for controlling the pressing pressures of the left upper-arm cuff 14L and theleft ankle cuff 16L, and thereby controls the pressing pressures of the fourcuffs cuffs cuffs CPU 74 determines, according to a well-known oscillometric algorithm, blood pressure values of the superior limbs and the inferior limbs of the subject, based on the signals continuously supplied from the four static-pressure, filter circuits and the four pulse-wave filter circuits. - FIG. 5 is a flow chart for explaining essential control functions of the
CPU 74 that are needed for determining a pulse-wave propagation velocity PWV The present pulse-wave-propagation-velocity-relatedinformation obtaining apparatus 10 is arranged to determine a pulse-wave propagation velocity at which a pulse wave propagates to the right upper arm and the right ankle, and a pulse-wave propagation velocity at which a pulse wave propagates to the right upper arm and the left ankle. Since the respective control functions of theCPU 74 for determining the two pulse-wave propagation velocity values PWV are identical with each other, the control routine of FIG. 5 shows the control functions for determining the pulse-wave propagation velocity at which the pulse wave propagates to the right upper arm and the right ankle. - The
CPU 74 carries out Step S1 (hereinafter, “Step” is omitted, if appropriate) to drive theair pumps 60 of the cuff-pressure changing portions pressure control valves 54 of the cuff-pressure changing portions - S1 is followed by S2 in which the
CPU 74 reads in respective one-heartbeat lengths of the cuff-pulse-wave signals SM1, SM3 respectively supplied from the pulse-wave filter circuits air pumps 60 and operate thepressure control valves 54 of the cuff-pressure changing portions - Subsequently, the CPU carries out S4 to determine a time of detection of a reference point of the cuff pulse wave represented by the signal SM1 and a time of detection of a corresponding reference point of the cuff pulse wave represented by the signal SM3, which signals SM1, SM3 have been read in at S2. As the reference point, a rising point or a peak point of each cuff pulse wave is employed. S4 is followed by S5 in which the
CPU 74 obtains, as a pulse-wave propagation time DT, a time difference between the times of detection of the two reference points of the two cuff pulse waves. - S5 is followed by S6 to obtain, according to the following Expression (1), a propagation distance L1 as a difference between respective distances of the right upper arm and the right ankle from the heart of the subject, based on the stature T inputted through the
input keys 44. - L1=aT+b Expression (1)
- (a and b are experimentally determined constants)
- S6 is followed by S7 in which the
CPU 74 substitutes the pulse-wave propagation time DT obtained at S5 and the pulse-wave propagation distance L1 obtained at S6, with the following Expression (2), thereby determining a pulse-wave propagation velocity PWV. In addition, theCPU 74 operates thedisplay device 46 to display the determined pulse-wave propagation velocity PWV. - PWV=L1DT Expression (2)
- In the illustrated pulse-wave-propagation-velocity-related
information obtaining apparatus 10 wherein the cuff-pulse-wave detecting units first pressure sensors main body 12 and the right upper-arm cuff 14R, and between themain body 12 and the left and right ankle cuffs 16L, 16R, the distances between the right upper-arm cuff 14R and thefirst pressure sensor 30 and between the left and right ankle cuffs 16L, 16R and thefirst pressure sensor 39 are shorter than those of a conventional arrangement whereinfirst pressure sensors main body 12. Accordingly, the present arrangement effectively reduces a time required for the cuff pulse waves produced in thecuffs first pressure sensors - In the illustrated pulse-wave-propagation-velocity-related
information obtaining apparatus 10, the length of thepipe 18 connecting between thecuff 14R and thefirst pressure sensor 30, the length of thepipe 24 connecting between thecuff 16L and thefirst pressure sensor 39, and the length of thepipe 26 connecting between thecuff 16R and thefirst pressure sensor 39, are made sufficiently short such that the time needed for the cuff pulse waves produced in thecuffs pipes pressure sensors CPU 74 at which the cuff-pulse-wave signals SM1, SM3 are read in. Accordingly, the cuff pulse waves obtained by the present apparatus are substantially free from the problem of time or phase delay. - In the illustrated pulse-wave-propagation-velocity-related
information obtaining apparatus 10, the cuff pulse waves substantially free from the problem of time delay are used as the two heartbeat-synchronous signals used for determining the pulse-wave propagation velocity PWV, so that the pulse-wave propagation velocity PWV can be accurately determined. - While the present invention has been described in detail in its presently preferred embodiment by reference to the drawings, the present invention may otherwise be embodied.
- In the illustrated pulse-wave-propagation-velocity-related
information obtaining apparatus 10, thefirst pressure sensor 30 is provided between thecuff 14R and themain body 12 and thefirst pressure sensors 39 are provided between thecuffs main body 12. Thefirst pressure sensor 30 may be provided in thecuff 14R or supported by thecuff 14R, and thefirst pressure sensors 39 may be respectively provided in thecuffs cuffs - In the illustrated pulse-wave-propagation-velocity-related
information obtaining apparatus 10, the two cuff pulse waves are used as the two heartbeat-synchronous signals for determining the pulse-wave propagation velocity PWV. As one of the two heartbeat-synchronous signals, there may be used any one of a heart sound, an electrocardiographic waveform (electrocardiogram), and a photoelectric pulse wave detected by a photoelectric-pulse-wave detecting sensor adapted to be worn on, e.g., an end portion of a finger of a living subject. - Moreover, in the illustrated pulse-wave-propagation-velocity-related
information obtaining apparatus 10, the pulse-wave filter circuits wave detecting units wave filter circuits main body 12. - The cuff pulse waves extracted by the pulse-
wave filter circuits - The present invention may be embodied with various changes without departing from the spirit thereof.
Claims (14)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2002-241701 | 2002-08-22 | ||
JP2002241701A JP3657584B2 (en) | 2002-08-22 | 2002-08-22 | Cuff pulse wave detector and pulse wave velocity information measuring device |
Publications (1)
Publication Number | Publication Date |
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US20040039290A1 true US20040039290A1 (en) | 2004-02-26 |
Family
ID=31492495
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US10/395,300 Abandoned US20040039290A1 (en) | 2002-08-22 | 2003-03-25 | Cuff pulse wave detecting apparatus and pulse-wave-propagation-velocity-related information obtaining device |
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Country | Link |
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US (1) | US20040039290A1 (en) |
EP (1) | EP1393670A3 (en) |
JP (1) | JP3657584B2 (en) |
Cited By (7)
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US20040010548A1 (en) * | 2002-07-11 | 2004-01-15 | International Business Machines Croporation | Apparatus and method for enhancing voicemail functionality with conferencing capabilities |
US20060195034A1 (en) * | 2003-04-01 | 2006-08-31 | Falko Skrabal | Device and method for the continuous non-invasive measurement of blood pressure |
US20150018631A1 (en) * | 2013-07-14 | 2015-01-15 | Avita Corporation | Apparatus and Method for Measuring Physiological Signals |
US20170021084A1 (en) * | 2014-05-15 | 2017-01-26 | Novalung Gmbh | Medico-technical measuring device and measuring method |
US10463306B2 (en) | 2014-05-15 | 2019-11-05 | Novalung Gmbh | Medical measuring system and method for production of the measuring system |
US10814054B2 (en) | 2015-10-23 | 2020-10-27 | Novalung Gmbh | Intermediate element for a medical extracorporeal fluid line, and system and method associated therewith |
US11219380B2 (en) | 2016-06-24 | 2022-01-11 | Omron Healthcare Co., Ltd. | Blood pressure pulse wave measurement apparatus |
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TW200819109A (en) * | 2006-10-20 | 2008-05-01 | Univ Chang Gung | Finger-wearing type pulse-feeling apparatus |
US7868757B2 (en) * | 2006-12-29 | 2011-01-11 | Nokia Corporation | Method for the monitoring of sleep using an electronic device |
DE102007052222A1 (en) * | 2007-10-31 | 2009-05-14 | Bosch + Sohn Gmbh & Co. Kg | Apparatus and method for determining the ankle-brachial index of a subject |
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US20040010548A1 (en) * | 2002-07-11 | 2004-01-15 | International Business Machines Croporation | Apparatus and method for enhancing voicemail functionality with conferencing capabilities |
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US20170021084A1 (en) * | 2014-05-15 | 2017-01-26 | Novalung Gmbh | Medico-technical measuring device and measuring method |
US10391227B2 (en) * | 2014-05-15 | 2019-08-27 | Novalung Gmbh | Medico-technical measuring device and measuring method |
US10463306B2 (en) | 2014-05-15 | 2019-11-05 | Novalung Gmbh | Medical measuring system and method for production of the measuring system |
US11357899B2 (en) | 2014-05-15 | 2022-06-14 | Novalung Gmbh | Measuring device and method for measuring a property of a fluid in a line |
US10814054B2 (en) | 2015-10-23 | 2020-10-27 | Novalung Gmbh | Intermediate element for a medical extracorporeal fluid line, and system and method associated therewith |
US11219380B2 (en) | 2016-06-24 | 2022-01-11 | Omron Healthcare Co., Ltd. | Blood pressure pulse wave measurement apparatus |
Also Published As
Publication number | Publication date |
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JP2004073721A (en) | 2004-03-11 |
EP1393670A3 (en) | 2004-04-14 |
JP3657584B2 (en) | 2005-06-08 |
EP1393670A2 (en) | 2004-03-03 |
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